This content originally appeared on DEV Community 👩💻👨💻 and was authored by Mazin Idris
What exactly is routing?
When there's an HTTP request from the user to the application, it should be directed to the right controller. You can picture a router as a receptionist at who connects you to the right person to talk to.
How is routing done in Ruby on Rails?
In Rails, the routes of your application live in config/routes.rb. The Rails router recognises URLs and dispatches them to a controller's action. It can also generate paths and URLs, avoiding the need to hardcode strings in your views. Let's consider an application to book rooms in different Hotels and take a look at how this works.
Types of HTTP request methods:
The application receives an HTTP request which carries along with it a method which could be:
- GET - Retrieve a resource
- POST - Create a resource
- PUT - Completely update a resource
- PATCH - Partially update a resource
- DELETE - Delete a resource
These methods determine which controller action method is called.
Decoding the http request
If the application receives the request, GET /players/1. The request is dispatched to the players controller's show action with { id: '1' } in params.
get '/teams/:id', to: 'teams#show'
Similarly,
get '/teams', to: 'teams#index'
get '/teams/:id', to: 'teams#show'
get '/teams/new', to: 'teams#new'
post '/teams', to: 'teams#create'
get '/teams/:id/edit', to: 'teams#edit'
put '/teams/:id', to: 'teams#update'
delete '/teams/:id', to: 'teams#destroy'
Defining resources
Like how the receptionist holds a record of all the reservations, the application too has its own record in config/routes.rb.
Rails.application.routes.draw do
resources :teams
end
By writing resources :teams we create all seven different routes in your application, all mapping to the Hotels controller like mentioned above.
If your controller has only a few of these actions you can alter the same with the following keywords.
The keyword only includes only the actions mentioned. resources :teams, only: [:edit]
There's also the keyword except to name the ones you don't want to include.
resources :teams, except: [:index]
resources :players,
resources :teams
Nested Resources
Sometimes we have nested routes, /teams/:id/players which are a result of resources that are logically children of other resources. For example, suppose your application includes these models:
class Team < ApplicationRecord
has_many :players
end
class Player < ApplicationRecord
belongs_to :teams
end
In which case we will declare our resources this way,'
resources :teams do
resources :players
end
This declaration helps us access the nested URLs such as /teams/:id/players , /teams/:id/players/:id , /teams/:id/players/new etc
This content originally appeared on DEV Community 👩💻👨💻 and was authored by Mazin Idris
